We present two experiments in which the interplay between
stretching and bending modes in thin elastic plates plays an
important role. The first experiment is motivated by the
understanding of plant leaf shape (e.g. Maize leaves, grass).
During growth, many leaves unfold to become flat while their
bottom is still attached to the cylindrical stem. We investigate
the mechanical analogue of this unfold length and address the
question: what is the persistence length of a curvature applied
at one end of a flat elastic strip? Simple scaling arguments are
compared to experiments and numerical simulations using Surface
Evolver. The second experiment concerns the snap-buckling
instability of highly deformed plates, in relation to the noise
of crumpling. Using high-speed video and
three-dimensional shape reconstruction, we show that
snap-buckling instabilities in thin plates are non-homogeneous
and occur via the very fast propagation of an elastic defect. The
speed of the transition and the acoustic signature of the snap
are mainly controlled by the defect size.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.H11.3